Baseband encoding method and apparatus for increasing the transmission rate over a communication medium

Abstract

An encoder for encoding binary data bits supplied by a data source into pulse amplitude modulated multilevel symbols. The encoder includes a bit stuffer for receiving the data bits from the data source at a first data bit rate, which at most equals a maximum data bit rate. The bit stuffer then adds descriptive bits to the data bits at a descriptive bit rate, which at most equals a maximum descriptive bit rate. The encoder also includes a multilevel pulse amplitude modulator for receiving the data and descriptive bits from the bit stuffer and for converting the data and descriptive bits into pulse amplitude modulated multilevel symbols. When these multilevel PAM symbols are transmitted, they have a spectral energy characteristic which is below a predetermined low level threshold at a predetermined baseband bandwidth frequency. In addition, these multilevel PAM symbols have a symbol rate (i.e., baud rate) which at most equals a maximum baud rate when the first data bit rate equals the maximum data bit rate and the descriptive bit rate equals the maximum descriptive bit rate. In turn, the magnitude of the maximum baud rate equals the magnitude of the baseband bandwidth frequency.

I claim: 
     
       1. An encoder for encoding binary data bits supplied by a data source into multilevel pulse amplitude modulated symbols, wherein said symbols are transmitted over a transmission medium subject to a maximum baseband bandwidth frequency, said encoder comprising: a bit stuffer for receiving said data bits at a first data bit rate from said data source, said bit stuffer adding descriptive bits to said data bits at a descriptive bit rate, wherein said first data bit rate at most equals a maximum data bit rate and said descriptive bit rate at most equals a maximum descriptive bit rate; and   a modulator for receiving said data and descriptive bits from said bit stuffer and for converting said data and descriptive bits into multilevel pulse amplitude modulated symbols having a baud rate, wherein said baud rate at most equals a maximum baud rate when said first data bit rate equals the maximum data bit rate and said descriptive bit rate equals the maximum descriptive bit rate, wherein said maximum baud rate has a magnitude equal to a magnitude of said baseband bandwidth frequency such that surplus spectral energy within the baseband bandwidth is utilized for said descriptive bits.   
     
     
       2. The encoder of claim 1, wherein said descriptive bits are delimiter bits. 
     
     
       3. The encoder of claim 1, wherein said descriptive bits are parity bits for maintaining a predetermined bit error rate and a predetermined hamming distance while increasing the first data bit rate from a second lower data bit rate to the maximum data bit rate. 
     
     
       4. The encoder of claim 1, wherein said multilevel pulse amplitude modulated symbols have at least three levels and whose spectral characteristic shows an energy null at the baseband bandwidth frequency when transmitted. 
     
     
       5. The encoder of claim 1, wherein said encoder is an Ethernet network encoder. 
     
     
       6. The encoder of claim 1, wherein said modulator is a 2B-1Q modulator. 
     
     
       7. An Ethernet encoder for encoding input data bits supplied by a data source into multilevel pulse amplitude modulated symbols having at least three levels and for supplying said symbols to a channel A twisted pair cable and a channel B twisted pair cable, wherein said symbols are transmitted over said twisted pair cables subject to a maximum baseband bandwidth frequency, said encoder comprising: a) a splitter for receiving said input data bits at a first data bit rate from said data source and for splitting said input data bits into channel A data bits and channel B data bits;   b) a channel A bit stuffer for receiving said channel A data bits from said splitter and for adding channel A descriptive bits to said channel A data bits at a channel A descriptive bit rate, wherein said channel A descriptive bit rate at most equals a maximum channel A descriptive bit rate;   c) a channel B bit stuffer for receiving said channel B data bits from said splitter and for adding channel B descriptive bits to said channel B data bits at a channel B descriptive bit rate, wherein said channel B descriptive bit rate at most equals a maximum channel B descriptive bit rate;   d) a channel A modulator for receiving said channel A data and descriptive bits from said channel A bit stuffer, converting said channel A data and descriptive bits into channel A multilevel pulse amplitude modulated symbols having a channel A baud rate, and supplying said channel A symbols to said channel A twisted pair cable; and   e) a channel B modulator for receiving said channel B data and descriptive bits from said channel B bit stuffer, converting said channel B data and descriptive bits into channel B multilevel pulse amplitude modulated symbols having a channel B baud rate, and supplying said channel B symbols to said channel B twisted pair cable;   f) wherein said channel A and channel B baud rates at most equal a maximum baud rate when said first data bit rate equals the maximum data bit rate and said descriptive bit rates equal the maximum descriptive bit rates, said maximum baud rate having a magnitude equal to a magnitude of said baseband bandwidth frequency.   
     
     
       8. The Ethernet encoder of claim 7, wherein said descriptive bits are delimiter bits. 
     
     
       9. The Ethernet encoder of claim 7, wherein said descriptive bits are parity bits for maintaining a predetermined bit error rate and a predetermined hamming distance while increasing the first data bit rate from a second lower data bit rate to the maximum data bit rate. 
     
     
       10. The Ethernet encoder of claim 9, wherein said channel A parity bits are even parity bits and said channel B parity bits are odd parity bits. 
     
     
       11. The Ethernet encoder of claim 9, wherein said baseband bandwidth frequency is 30 MHz, said maximum data bit rate is 100 MBits/s, said second lower data bit rate is 10 MBits/s, said bit error rate is below 10 -9 , and said hamming distance is at least 4. 
     
     
       12. The Ethernet encoder of claim 7, wherein said baseband bandwidth frequency is 30 MHz and said maximum data bit rate is 100 MBits/s. 
     
     
       13. The Ethernet encoder of claim 7, wherein said pulse amplitude modulated multilevel symbols are 2B-1Q symbols. 
     
     
       14. The Ethernet encoder of claim 7 adapted to operate in a two twisted pair half-duplex Ethernet encoding and decoding apparatus. 
     
     
       15. The Ethernet encoder of claim 7 adapted to operate in a four twisted pair full-duplex Ethernet encoding and decoding apparatus. 
     
     
       16. A four twisted pair full-duplex Ethernet encoding and decoding system comprising: a) a first encoder for coupling to a first data node to receive a first set of input data bits, said first encoder encoding said first set of input data bits into a first set of multilevel pulse amplitude modulated symbols having at least three levels;   b) a second encoder for coupling to a second data node to receive a second set of input data bits, said second encoder encoding said second set of input data bits into a second set of multilevel pulse amplitude modulated symbols having at least three levels;   c) a channel A twisted pair cable and a channel B twisted pair cable receiving said first set of symbols from said first encoder at a channel A baud rate and a channel B baud rate;   d) a channel C twisted pair cable and a channel D twisted pair cable receiving said second set of symbols from said second encoder at a channel C baud rate and a channel D baud rate, wherein when said symbols are supplied to said twisted pair cables said symbols are subject to a maximum baseband bandwidth frequency;   e) a first decoder for coupling to said second data node to supply said first set of input data bits to said second data node, said first decoder receiving said first set of symbols from said channel A and B twisted pair cables and decoding said first set of symbols into said first set of input data bits; and   f) a second decoder for coupling to said first data node to supply said second set of input data bits to said first data node, said second decoder receiving said second set of symbols from said channel C and D twisted pair cables and decoding said second set of symbols into said second set of input data bits;   g) wherein said channel A, B, C, and D baud rates at most equal a maximum baud rate having a magnitude equal to a magnitude of said baseband bandwidth frequency.   
     
     
       17. The Ethernet encoding and decoding apparatus of claim 16, wherein said first encoder comprises: a) a splitter for receiving said first set of input data bits at a first data bit rate from said first data node and for splitting said first set of input data bits into channel A data bits and channel B data bits;   b) a channel A bit stuffer for receiving said channel A data bits from said splitter and for adding channel A descriptive bits to said channel A data bits at a channel A descriptive bit rate, wherein said channel A descriptive bit rate at most equals a maximum channel A descriptive bit rate;   c) a channel B bit stuffer for receiving said channel B data bits from said splitter and for adding channel B descriptive bits to said channel B data bits at a channel B descriptive bit rate, wherein said channel B descriptive bit rate at most equals a maximum channel B descriptive bit rate;   d) a channel A modulator for receiving said channel A data and descriptive bits from said channel A bit stuffer, converting said channel A data and descriptive bits into channel A multilevel pulse amplitude modulated symbols having said channel A baud rate, and supplying said channel A symbols to said channel A twisted pair cable; and   e) a channel B modulator for receiving said channel B data and descriptive bits from said channel B bit stuffer, converting said channel B data and descriptive bits into channel B multilevel pulse amplitude modulated symbols having said channel B baud rate, and supplying said channel B symbols to said channel B twisted pair cable;   f) wherein said channel A and channel B baud rates at most equal said maximum baud rate when said first data bit rate equals the maximum data bit rate and said descriptive bit rates equal the maximum descriptive bit rates.   
     
     
       18. The Ethernet encoder of claim 17, wherein said descriptive bits are delimiter bits. 
     
     
       19. The Ethernet encoder of claim 17, wherein said descriptive bits are parity bits for maintaining a predetermined bit error rate and a predetermined hamming distance while increasing the first data bit rate from a second lower data bit rate to the maximum data bit rate. 
     
     
       20. The Ethernet encoder of claim 19, wherein said channel A parity bits are even parity bits and said channel B parity bits are odd parity bits. 
     
     
       21. The Ethernet encoder of claim 19, wherein said baseband bandwidth frequency is 30 MHz, said maximum data bit rate is 100 MBits/s, said second lower data bit rate is 10 MBits/s, said bit error rate is below 10 -9 , and said hamming distance is at least 4. 
     
     
       22. The Ethernet encoder of claim 17, wherein said baseband bandwidth frequency is 30 MHz and said maximum data bit rate is 100 MBits/s. 
     
     
       23. The Ethernet encoder of claim 17, wherein said pulse amplitude modulated multilevel symbols are 2B-1Q symbols. 
     
     
       24. An encoding method for encoding binary data bits supplied by a data source into multilevel pulse amplitude modulated symbols, wherein said symbols are transmitted over a transmission medium subject to a maximum baseband bandwidth frequency, said encoding method comprising the steps of: receiving said data bits at a first data bit rate from said data source;   adding descriptive bits to said data bits at a descriptive bit rate, wherein said first data bit rate at most equals a maximum data bit rate and said descriptive bit rate at most equals a maximum descriptive bit rate; and   converting said data and descriptive bits into multilevel pulse amplitude modulated symbols having a baud rate, wherein said baud rate at most equals a maximum baud rate when said first data bit rate equals the maximum data bit rate and said descriptive bit rate equals the maximum descriptive bit rate, wherein said maximum baud rate has a magnitude equal to a magnitude of said baseband bandwidth frequency such that surplus spectral energy within baseband bandwidth is utilized for said descriptive bits.   
     
     
       25. The encoding method of claim 24, wherein said descriptive bits are parity bits for maintaining a predetermined bit error rate and a predetermined hamming distance while increasing the first data bit rate from a second lower data bit rate to the maximum data bit rate. 
     
     
       26. The encoding method of claim 24, wherein said pulse amplitude modulated multilevel symbols are 2B-1Q symbols. 
     
     
       27. An Ethernet encoding method for encoding input data bits supplied by a data source into multilevel pulse amplitude modulated symbols having at least three levels and for supplying said symbols to a channel A twisted pair cable and a channel B twisted pair cable, wherein said symbols are transmitted over said twisted pair cables subject to a maximum baseband bandwidth frequency, said encoding method comprising the steps of: a) receiving said input data bits at a first data bit rate from said data source;   b) splitting said input data bits into channel A data bits and channel B data bits;   c) adding channel A descriptive bits to said channel A data bits at a channel A descriptive bit rate, wherein said channel A descriptive bit rate at most equals a maximum channel A descriptive bit rate;   d) adding channel B descriptive bits to said channel B data bits at a channel B descriptive bit rate, wherein said channel B descriptive bit rate at most equals a maximum channel B descriptive bit rate;   e) converting said channel A data and descriptive bits into channel A multilevel pulse amplitude modulated symbols having a channel A baud rate, and supplying said channel A symbols to said channel A twisted pair cable; and   f) converting said channel B data and descriptive bits into channel B multilevel pulse amplitude modulated symbols having a channel B baud rate, and supplying said channel B symbols to said channel B twisted pair cable;   g) wherein said channel A and channel B baud rates at most equal a maximum baud rate when said first data bit rate equals the maximum data bit rate and said descriptive bit rates equal the maximum descriptive bit rates, said maximum baud rate having a magnitude equal to a magnitude of said baseband bandwidth frequency.   
     
     
       28. The Ethernet encoding method of claim 27, wherein said descriptive bits are parity bits for maintaining a predetermined bit error rate and a predetermined hamming distance while increasing the first data bit rate from a second lower data bit rate to the maximum data bit rate. 
     
     
       29. The Ethernet encoding method of claim 27, wherein said channel A parity bits are even parity bits and said channel B parity bits are odd parity bits. 
     
     
       30. The Ethernet encoding method of claim 27, wherein said pulse amplitude modulated multilevel symbols are 2B-1Q symbols. 
     
     
       31. The Ethernet encoding method of claim 27 adapted to operate in a two twisted pair half-duplex Ethernet encoding and decoding method. 
     
     
       32. The Ethernet encoding method of claim 27 adapted to operate in a four twisted pair full-duplex Ethernet encoding and decoding method.